This invention relates to a sample introducing system and more particularly to a system for introducing samples into an evacuated chamber for analysis without venting any significant volume of air into the chamber.
The invention is useful, for example, in introducing a sample into the evacuated chamber of an electron spectrometer or electron microscope. In Instruments of this type, the analysis chamber is under vacuum and significant time is required to pump out the chamber after it is opened to the atmosphere. The typical prior art practice for introducing and removing samples involves an air lock having a secondary or intermediate chamber. The sample is transferred first from the atmosphere into the intermediate chamber which is then sealed and evacuated. Subsequently, the sample is transferred into the instrument chamber. U.S. Pat. Nos. 2,666,539; 2,852,683; 2,910,590; and 3,218,457 illustrate various prior art systems.
Among the several objects of the present invention may be noted the provision of a system for introducing a sample into an evacuated compartment without venting the chamber and without requiring an intermediate air lock chamber which must be repeatedly evacuated and vented; the provision of such apparatus which admits very little air into the evacuated chamber during the introduction of a sample; the provision of such an apparatus which may be simply and rapidly operated; and the provision of such apparatus which is reliable and is of relatively simple and inexpensive construction. Other objects and features will be in part apparent and in part pointed out hereinafter.